The present disclosure relates to an image reading device which reads image data from a document placed on a document table.
Generally, there is known an image reading device that radiates light from below to a document placed on a document table and receives the reflected light by a photoelectric conversion element such as a CCD, thereby reading image data from the document. In the case where, by using this type of image reading device, image data is read from a thick document (hereinafter, referred to as a “book document”) such as a book formed by a plurality of sheets bound at the center, a gap occurs between the document table and a central portion of the book document. Therefore, the amount of light reflected from the central portion of the book document decreases, so that a black belt-like image appears at the central portion of the book document in image data read by the image reading device. Considering this, there is known an image processing device that has a special sensor for detecting the height of the central portion of a book document placed on a document table, and that converts a black belt-like image in image data into a white image in accordance with a result of detection by the sensor.